Cholinergic Flashcards
Pilocarpine
Cholinergic agonist
Decreases intraocular pressure (narrow angle glaucoma)
SE: blurry vision, brow ache, miosis, SWEATING, SALIVATION
Methacholine
Cholinergic agonist
Bronchoconstriction (used to diagnose asthma)
Bethanechol
most GI effect; Increase peristalsis, motility, and secretions
Increase Urination
cholinergic GI effect
Bethanechol (most)
Pilocarpine (not as much)
Used for underactive bladder
Bethanechol
Cause sweating
Pilocarpine (MOST)
Muscarine
Acrecoline (betel nuts)
Direct cholinergic drugs
Ach Bethenachol Pilocarpine Cevemiline Nicotine Varenicline
Cause significant salivation
PILOCARPINE
cevimeline
What effect does IV Ach have that parasympathetics don’t?
Vasodilation (NO/EDGF) & Sweating
Bethanechol
Quaternary – No CNS
Resistant to AchE
Selective- muscarinic receptors
Urinary/GI effects
Tertiary Nitrogen
Pilocarpine- CNS to some degree
Pilocarpine, Muscarine
alkaloids
Selective for muscarinic
readily absorbed orally
Pilocarpine- Tertiary N – some CNS penetration
Sweat and salivation glands sensitive to pilocarpine
Cevimeline
M1 and M3, but mainly selective for M1; therefore, causes less sweating than pilocarpine
M1
salivation
M3
sweating, lacrimation, miosiss
Nicotine
selective for nicotinic receptors; patches used to quit smoking
Varenicline
partial agonist on nicotinic receptor subtype in brain
causes just enough dopamine release to relieve craving, makes smoking less pleasurable
SE: N/V, fatigue, H/a, constipation, FLATULENCE
CNS effects: sleep disturbance, vivid nightmares, pyschosis, mania, suicide
Muscarine
found in some mushrooms
Pilocarpine use
narrow-angle glaucoma
Tx for postop abdominal distention or gastric atony
Bethanechol
Tx for urinary retention
Bethanechol
Sjogren’s tx (or dry mouth from radiation)
Cevimeline (1st)
Pilocarpine (less so b/c sweating side effect)
Muscarine agonist SE
sweating salivation Blurry vision Abdominal cramping, N/V/D Cutaneous vasodilation Bronchoconstriction bladder tightness
Contraindications for muscarinic agonists
PEPTIC ULCER
coronary insufficiency
ASTHMA/COPD
bowel obstruction
Muscarine poisoning from mushrooms
salivation, tears N/V/D h/a, visual disturbance bronchospasm bradycardia, shock
Tx muscarine poisoning
atropine (antagonist) and albuterol (reverse bronchonstriction)
Central effects of nicotine
low dose: alertness & attention
High dose: tremor, vomiting, increased respiration
Toxic: convulsions
Peripheral effects of nicotine
both sympathetic and parasympathetic
Heart (sym): increase HR, HTN; may alternate w/ vagal bradycardia
GI (parasym): N/V/D, urination
NMJ: initially causes twitches or contraction, progresses to desnsitization of NMJ and flaccid paralysis
Nicotine toxicity
Vomiting
CNS: convulsions, coma, respiratory arrest
NMJ block/paralysis
HTN, Cardiac arrhythmia
Tx for nicotine toxicity
atropine (blocks muscarinic receptors- dec. parasym effects)
Anticonvulsants
Assist respiration
Why can’t you block nicotinic receptors in nicotine toxicity
they are all already block or desensitized
Cholinesterase Inhibitors
Carbamates
Edrophonium
Echothiophate
Organophosphate pesticides
Organophosphates
DFP, echothiopate, soman, sarin, parathion, malathion
Neostigmine MOA
tertiary N is attracted to negative oxygen on AchE; bind the oxygen and blocks enzymes actions; slowly hydrolyzed/released from enzyme
Carbamates
Neostigmine
Pyridostigmine
Pysostigmine
Use of cholinesterase inhibitors
reverse nerve block after surgery
Carbamate MOA
form covalent bond with AchE; last 30 mins-6 hours
Quaternary carbamates
Neostigmine and pyridostigmine – not well absorbed orally, DO NOT cross BBB
Tertiary Carbamate
Physostigmine – well absorbed orally, will get into brain
Edrophonium
Must be injected; VERY SHORT DURATION (5-10 minutes)